Folder

What is a Folder in a Computer?

A folder is a virtual object where you can put "items" inside. Folders are used to organize items when you have too many items. What are these "items" exactly depends on the context. In any context, you'll often be able to place folders inside other folders—which means a folder is one type of item—thus creating a hierarchical folder structure, also called a "tree" structure.

Typically, when we talk about folders, we're talking about folders in a file system, where the "items" are computer files. This type of folder is also called a directory (abbreviated "dir"). When you have too many files in your PC, to organize them you put them into folders. A brand new computer with an operating system installed in it will already have countless folders, because folders are also a way for the operating system to organize its own files.

In general, a folder in a program is a group of items, where each item can only belong to one group. There are also cases where a function of a program uses a folder icon, but actually has a filter function, which would filter the items based on some filter criteria, e.g. "all items that are images."